Disazo dyestuff.



UNITED STATES PATENT OFFICE.

AUGUST LEOPOLD LASKA, 0F OFFENBAGH-ON-THE-MAIN, GERMANY, ASSIGNOR TO CORPORATION OF CHEMISCHE FABRIK GRIESHEIM-ELEKTRON, 0F FRANKFURT- ON-THE-MAIN, GERMANY.

DISAZO DYESTUFF.

No Drawing.

To all whom it may concern:

Be it known that I, AUGUST LnoroLD LASKA, doctor of philosophy, chemist, a sub ject of the German Emperor, and resident of Offenbach-on-the-Main, in the Grand Duchy of Hesse, Germany, with the post-ofiice address Gerberstrasse 5, have invented new and useful Improvements in Disazo Dyestufi', of which the following is a specification.

My invention relates to the production of a red disazo dyestufi consisting in combining the tetrazo compound of dichlorodinitrobenzidin probably having the following constitution:

which can be obtained by nitration of the diacetyl compound of meta-meta-dichlorobenzidin (NI-I :Cl=1:3) with nitric acid corresponding to two molecules and by splitting 011 the acidyl groups from the reaction product, with two molecules of fl-naphthol.

The dyestufi is insoluble in water and ad vantageously used in pasty form; it is solulole in concentrated sulfuric acid with bluered color. The dyestuff is completely insoluble in oil and can be used for the preparation of red pigment colors.

Eazample I. Preparation of the dz'chlorodintr0bemid'in.Meta-meta-dichlorobenzidin is transformed in the usual manner into the diacetyl compound; 16.8 parts of the meta meta dichlorodiacetylbenzidin well cooled with ice are dissolved in 100 parts of sulfuric acid 66 B. and at a temperature of O5 C. and the nitric acid corresponding to two molecular proportions gradually is added. Then the mixture is heated to 20 C. and the reaction product is poured into ice water. The precipitated dichlorodinitrodiacetylbenzidin is filtered off and the acidylgroups are split off by heating with sulfuric acid having a strength of 25 per cent. The dichlorodinitrobenzidin forms a yellow powder and has a melting point of about 255 de grees centigrade.

Eaampie [1. Preparation of the dyestafi.- 34.3 parts of dichlorodinitrobenzidin are sufiiciently ground with 200 parts of water and 80 parts of hydrochloric acid 20 Baum Specification of Letters Patent.

Application filed July 15, 1910.

Patented Jan. 24, 1911.

Serial No. 572,099.

and diazotized with 14 parts of sodium nitrite. The rcsulting solution, which if necessary may be filtered, is introduced in 29 parts of ,B-naphthol, which is precipitated from a solution of the corresponding quan tity of the sodium salt of B-naphthol in 500 parts of water in presence of Turkey red oil, and to which is added 140 parts of sodium acetate. The combination is quickly completed and the dyestufi is precipitated in form of red flakes. It is filtered oflf, washed with water and advantageously used in pasty form. The dyestuff is insoluble in water and soluble in concentrated sulfuric acid with a blue-red color.

Instead of the Turkey red oil can be used other similar acting ingredients, for instance soap or resin-lime or the combination can be made in absence of one of these ingredients. The combination of the tetrazo compound with ,G-naphthol can be made in presence of a substratum.

Now what I claim and desire to secure by Letters Patent is the following:

1. The process for the production of a disazo dyestuff consisting in combining the tetrazo compound of the dichlorodinitrobenzidin probably having the following constitution:

which can be obtained by nitration of the meta-meta-dichlorodiacetylbenzidin and by splitting off the acidyl group of the reaction product with two molecular proportions of ,B-naphthol, which dyestuff forms in dry state a dark-red powder, insoluble in Waiter presence of two Witnesses this 5th day of soluble in concentrated sulfuric acid with July 1910.

blue-red color and completely insoluble in oil and which can Well be used for the prepa- AUGUST LEOPOLD LASKA' ration of pigment colors. Witnesses:

In testimony, that I claim the foregoing as EVA SATTLER,

my invention, I have signed my name in HERMANN WEST. 

